Process for producing hard metal carbide alloys



March 12, 1940. P WRlGH-i' 2,193,413

PROCESS FOR PRODUCING HARD METAL CARBIDE ALLOYS Filed April 14, 1958 2Sheets-Sheet 1 March l2, 1940. P WRIGHT 2,193,413

PROCESS FOR PRODUCING HARD METAL CARBIDE ALLOYS Filed April 14, 1938 2Sheets-Sheet 2 32 34 "1"""\` M Ul` x A TTORN E YS.

Patented Mar. 12, 1940 PATENT OFFICE PROCESS FOR PROIXIUCING HARD METALCARBIDE ALLOYS Peter Wright, Hillside, N. J., assignor to Carl Eisen andJoseph J. Haesler, both of Montclair,

Application anni 14, 193s, serian No. 202,035

13 Claims.

This invention relates to hard metal carbide alloys useful for cuttingtools, tool bits. wearing parts, wire drawing dies, and other uses aswell as to a process for making such hard metal carbides. A

Hard metal carbides have been known for a long time and within the pastdecade have assumed considerable commercial importance particularly incompositions which are'principally n tungsten carbide or in whichtungsten carbide is the most important controlling element in so far aseither wear or cutting properties are concerned. In the commercialdevelopment of these hard metal carbides oi various compositions manyprocesses have been proposed for the preparation of the raw materials,reduction of oxides to metal where necessary, carburizing those metalswhich form carbides, forming the carbides into proper shapes for cuttingtools, wearing parts, tool tips and the like, heating the carbides tosinterng temperatures thereby forming hard alloys, etc. Thesedevelopments in hard metal carbides have not been confined to those inwhich tungsten carbide is the predominating property controllingmaterial. A number of suggestions have been made particularly in thepatented art of other metallic carbides alleged to have desirableproperties for the purpose to which the tungsten carbide alloys havebeen put. Among these suggestions is that of employing titanium carbide,usually, however, with the inclusion oi other metallic carbides. At thepresent time there is no commercially produced metal carbide in'whichtitanium carbide is present in the major proportion of the carbides ofthe alloy. Some commercial alloys have been prepared for particularpurposes in which are included up to about 25% 0; titanium carbide theremainder being principally tungsten carbide. Such commercial productshave been found to be extremely br'ttle and are useful only in verylimited flelds.

it has been proposed to prepare hard metal carbides comprising titaniumcarbide by the usual methods as applied to tungsten carbide whichincludes specifically the pressure forming of the article from thepowdered carbide and powdered auxiliary combining or eementing metalsand then sintering the formed article. However, these methods, whileapparently producing satisfactory hard alloys wherein the tungsten isthe predominating hard metal carbide, are not satisfactory to producetitanium carbide alloys.

l have discovered a method for producing hard,

metal carbide alloys that can be used for preparing various metalcarbide alloys but is peculiarly adapted for producing a titaniumcarbide alloy having superior properties to those heretofore attainednot only in titanium carbide alloys but also in the various tungstencarbide alloys.

The invention resides in a process for preparing refractory metalcarbides which comprises heating a metal carbide and an auxiliary metalto a temperature above the melting point of the auxiliary metal andbelow the melting point of the metal carbide then gradually applyingincreasing continuous pressures to the alloy accompanied by vibrationindependently applied until the temperature has fallen below the meltingpoint of any constituent of the alloy.

in a more specific sense the invention resides in a process forpreparing a titanium carbide alloy which comprises heating titaniumcarbide and auxiliary metals comprising chromium and nickel to atemperature above the melting point of at least one of the auxiliarymetals and below the melting point of the titanium carbide thengradually applying increasing pressures to thel alloy accompanied byvibration until the tern-l perature has fallen below the melting pointof any constituent of the alloy.

Another specic aspect of the invention resides in a process forpreparing hard metal carbide alloys which comprises preparing acomposition containing at least fty percent of titanium carbide and fromve to fifty percent of auxiliary metal comprising chromium and nickel,placing the composition in a mold, heating to an alloying temperatureabove the melting point oi the nickel and below the meltingpoint of theata- 35 nium carbide while applying a slight pressure to maintain theheated composition in contact with the mold, stopping the application ofheat and gradually applying increasing pressures accompanied byvibration until the alloy has been compressed in the ratio of to 125grams of original mixture to each cubic inch or nnished alloy and thetemperature is below the melting point of any constituent of the alloy.

A very specic aspect of the invention is the process for preparing hardmetal carbide alloys which comprises heating a mixture of approximatelyseventy-five percent of titanium carbide with approximately eightpercent of chromium and seventeen -percent of nickel under non-oxidizingconditions to a temperature above about 2000" centigrade and until themixture is alloyed to form a slightly shrunk frlable material, breakingup the said material, placing from 80 to 125 grams of the powderedmaterial ing the material until it is again at the alloying temperature,stopping the application of heat and gradually applying increasingpressures accompanied by vibration until the alloy has been compressedto the predetermined size and the temperature is below the melting pointof any constituent of the alloy.

My invention also provides a hard metal carbide alloy comprising a metalcarbide of the 4th, 5th or 6th periodic group and an auxiliary metal ofa member of the iron group with about one half as much chromiumthoroughly alloyed at a temperature below the melting point of thecarbide and having its maximum density.

Specifically my invention resides in a titanium carbide alloy comprisingapproximately seventyve parts of titanium carbide thoroughly alloyed ata temperature below the melting point of the titanium carbide withapproximately seventeen parts of nickel and eight parts of chromium, ofmaximum density and exhibiting a hardness of 9i on the Rockwell scale Auseful for cutting tools, dies and wearing surfaces.

'I'he invention will be speciilcally described with reference to certainpreferred embodiments thereof andrparticularly as applied to alloys inwhich titanium carbide is the principal metal carbide constituent but itwill be understood that many of the steps of the process are subject tomodification in the light of some of the general principals understoodin this art and also that certain features of the invention areapplicable to tungsten, tantalum or other hard metal carbides,silieides, tellurides or borides of the fourth, nfth and sixth groups ofthe periodic table or mixtures of them.

To prepare a hard titanium carbide alloy a mixture is made comprisingabout seventy-five parts of titanium carbide, eight parts oi chromiumand seventeen parts of nickel.

The titanium carbide should contain approximately seventeen percent ofcombined carbon i and be relatively free of graphitic carbon.Preferably, the titanium carbide is ground to a Very ne mesh. This canbe obtained by barreling titanium carbide for extended periods of timeas is well understood in the art. A f'lneness of at least 330 mesh ispreferable. The relative amount of the titanium carbide may be variedfrom as low as forty percent to as high as ninety- 'eight percent but ispreferably within about sixty percent to ninety percent of the originalmixture.

The chromium and nickel may be collectively considered as an auxiliarymetal or auxiliary metals. Broadly, in place of nickel the other membersof the iron group i. e. cobalt or iron,

may be substituted but While cobalt is preferable for tungsten carbide,nickell appears to give superior results with titanium carbide. Thesemetals either alone or in combination when alloyed with the titaniumcarbide serve as binding metals i. e., they cement the titanium carbideparticles together by an alloying action.

Such auxiliary metals may be present in varying amounts but increasingtheir relative proportion in the mixture while tending to increase thetoughness of the alloy also produces a softer or less abrasive product.Varying amounts may be employed from 1 or 2% to as high as 40 to butusually about 15%, not including the chromium is preferable.

'I'he chromium or an equivalent metal serves as the hardening agent inthe sense that while per cubic inch of finished alloy in a mold, heatthe binding metal produces a tough coherent product the presence of thebinding metal has a softening effect The presence of the chromium in theproportion of about half that of the metals of the iron group not onlyovercomes this softening effect but actually increases the hardness ofthe alloy produced. For best results the auxiliary metal should compriseat least 1% of chromium or other equivalent hardening metal.

It is usually satisfactory to add the auxiliary metals, the chromium andnickel, as metallic powders preferably finely ground, however,relatively coarse titanium carbide and the coarse powders of themetallic elements may be mixed and then barreled ground in a ball milltogether. Instead of mixing the ingredients as carbides and metals,titanium oxide may be mixed with oxides of the other metals which arereduced together and carburized to produce the titanium carbide. As analternative method, the prepared titanium carbide may be mixed withsolutions of chromium and nickel salts which are precipitated `on thetitanium carbide and reduced with a gaseous reducing agent as forexample, hydrogen. In any of these processes wherein the auxiliarymetals are added to the titanium carbide other than as finely groundmetallic powders, the mixtures must of course be barreled or ground toinsure minute subdivision and thorough'mixing.

After a suitable mixture of titanium carbide with proper proportions andamounts of auxiliary metals in finely divided form have been prepared itis, in the preferred embodiment of the invention, placed in a crucibleprovided with a nonoxidizing liner. Conveniently the lining of thecrucible may be magnesite, alundum, graphite or the like. 'Ihe cruciblecontaining the loose powder is then covered to prevent access of air orsubjected to an indifferent atmosphere and heated, conveniently in anelectric induction furnace to an alloying temperature preferably about2000 centigrade which may be described broadly as a temperature abovethe melting point of at least one of the auxiliary metals but below themelting point of the carbide. The heating, when small amounts of themixture are in a crucible, should continue for a few minutes after therequisite temperature has been attained, In the case of a cruciblecontaining 200 grams of mixture heated by a 25 KVA induction heater in acrucible surrounded by a layer of graphite a period of less than fifteenminutes after the material had been brought to heat was suilicient.

` 'I'his step as well as other heating steps may if ing ordisintegrating treatment to reduce it tok a powder but it has been foundpreferable to barrel this material to insure extreme neness of thealloy. 'I 'he flner the material is ground the better the properties ofthe ultimate product, asa general rule.

The pre-allowed titanium carbide and auxiliary metals after beingreduced to a powder of the degree of -iineness desired is then placed ina mold, hereinafter more specifically described which is made ofgraphite. 4Such molds are illustratedper se in Figures l to 4"of theaccompanying drawings and positioned lar line 3 3 .of Figure 1 showingthe powdered alloy in the mold 'and the plugs partly inserted as at thebeginning of a heat;

ligure 4 is a view also in section along the Iline d--ll vof 'Figure lshowing the mold, alloy and plugs at the end of a heat; and

Figure 5 is a view principally in elevation of the compression andvibrating apparatus associated with the furnace shown in section. Thegraphite mold is provided with recesses of the shape of the product tobe produced. These shapes will, of course, vary depending upon whethertool tips, tool bits, wearing parts or the like are to be produced. Eachof the recesses is also provided with tight tting graphite plugs whichhave a thickness less than the depth of the recess. The difference indepth .between the recess and the thickness of the plug would be thethickness or" the article to be produced and the dimensions of thisspace in the recess, which would not be lled when the plug has beenforced down to where its top is even with the surface of the mold, isconsidered the size of the ar ticle. This volume is carefully computedand for each cubic inch of volume there is introduced from 80 to 125grams of the prealloyed material. Where the composition of theprealloyed material '1s substantially '75 parts of titanium, thepreferred ratio is 95 to 100 grams per cubic inch. When the proportionof titanium carbide is increased the number of grams per cubic inch isreduced. For tungsten carbides, of higher density, ratios as high as 225to 250 grams per cubic inch are recommended depending on the amount ofbinder. Using the proper weight per volume is usually very important.

After the proper weight of prealloyed material has been put into themold, the plug or plugs, if more than one article is made in a singlemold, is inserted into the recess to lightly compact the material but isnot forced down with any substantial pressure. As the powderedprealloyed material has a substantially larger volume than the nishedarticle will have, the plugs project a substantial distance from thesurface of the mold.

The graphite mold is then placed in an induction furnace provided with agraphite lining which, along with the mold, is heated by induction. Themold is supported on a substantial base and a graphite post set on theplug on plugs. At the upper end of the graphite post, a body havingconsiderable inertia, as for example a steel bar weighing about 150pounds, is permitted to exert its weight on the graphite post therebyapplying pressure to the ppwdered alloy within the supported mold. Thispressure is constant but relatively light, being only suiiicient tofollow the creep of this metal'. I

After the mold has been placed in the furnace under the conditionsdescribed, the current is turned on to bring the contents of the furnaceup to heat. 'I'his temperature is about 2000 centigrade or slightlyhigher but below the melting point of the carbide. As the material isbrought up to heat the pressure exerted `by the steel bar maintains theprealloyed material within the mold in contact with the walls and doesnot permit it to creep away as it would if no pressure were beingapplied. The pressure being applied by the steel bar may be consideredas one suiiicient to maintain the material in the mold in contact withthe walls thereof which in the sense as herein used would include theplug as a wallv of the mold.

When' the temperature has reached approxivmately 2000 centigrade, it ismaintained for a short period of time which, in the case of tool bitsabout 21/2 inches long by inch square in a single mold was aboutminutes. The current for the induction furnace is cut oi and thepressure on the plugs in the mold or molds gradually increased in amanner that may be described generally as inversely of the fallingtemperature. At rst thepressure exerted is very slight then as thetemperature in the furnace falls, the pressure is increased but at sucha rate that the mold itself is not broken. Graphite molds under the hightemperature here employed will not withstand excessive pressures.. Thepressure is also raised in accordance with the feel of the alloy astransmitted through the handle of the hydraulic jack conveniently usedto apply the pressure.

The application of pressure to the steel bar and through it to theheated material in the mold is accompanied by vibration applied eitherthrough the mold or more conveniently on the plugs. Proper vibration isattained by sharp impacts on the steel bar. The direction, force, and.position on the steel bar to which the impacts are delivered may bevaried widely. For example, light but rapid tapping of one end of thebar with a small hammer has proved sucient. There is no directapplication of the impacts to the material in the mold. Obviously theimpacts may be delivered by hand while the operator is increasing thepressure or it may be attained by mechanical means. The combination ofpressure with vibration under the conditions described produces a hardmetal carbide alloy of maximum density for the constituents present.Such a condition insures superior performance of the hard metal carbideswhen used for the purposes to which they are adapted.

It has been found that pressures actually applied to the alloy are lessthan 1000 pounds per square inch and usually of the order of 600 poundsper square inch, based on the area of the plugs in contact with thealloy being limited by the strength of the mold. Such pressures areattained before the plugs are driven down into the mold so that theirexposed faces are substantially flush with the surface of the mold.After this condition has been attained, the further application ofpressure would be across the entire surface of the mold and thereby havea negligible effect in compressing the alloy within the mold.

This pressure and the driving of the plugs to the condition whereintheir tops are iush with the surface of the mold is attainedsubstantially at the time when the temperature of the alloy is justabove the melting point of any constituent of the alloy but the pressureis maintained until the contents of the furnace have fallen to below themelting point of any constituent of the alloy. Further cooling isusually desirable before removing the mold from the furnace. When themold is removed from the furnace while still hot 'Ill excludeatmospheric air.

When the mold and its contents have been.

cooled sufficiently, the hard metal carbide alloy is removed from themold as a finished product its shape corresponding to that of the moldin which it was formed.

The metal carbide alloy produced by this process when the compositioncomprises 75% titanium carbide with v25% of nickel and chromium in theapproximate ratio of two to 'one is a cutting material with a hardnessof 91 on the Rockwell Scale A. It has a high tensile strength above thatof the commercial tungsten carbide alloys. Its specific gravity isVapproximately Yone-half that of the usual tungsten carbide cuttingalloy. Because of the method of preparation alloys produced according tothis invention have the maximum density obtainable for the constituentspresent. constituents will affect the actual density but in all casesmaximum density is assured. In the processes of the prior art involvingpressing before sintering or forging after removal lfrom the furnace itwas not possible to insure freedom from pores. One of the importantprcrties of this alloy is its high heat resistance as a result of whichit can be used in cutting hard steels very rapidly so that the steelcomes off as a white hot spiral yet the tool does not break down orcrater.

lthough the alloy exhibits extreme hardness and is useful for fastcutting and freedom from fracture or cratering while giving longservice, it may be ground readily on a 60 mesh green grit wheel andnished on a 120 mesh green grit wheel. The alloys heretofore used ascutting alloys were particularly subject to the limitation that theycould not be satisfactorily ground and that after a tool had become dullit was impossible to regrincl it without so weakening its structure thatwhen reused it readily cracked in many instances.

In the preferred embodiment of the invention two principal steps areemployed, viz: prealloying followed by a second heating in amoldincluding pressure and vibration. It has been found that goodresults are also secured when finely ground carbide and thoroughly mixedauxiliary metal are placed directly in the mold as a loose powder in themanner heretofore described for the second heating in the mold. By thismethod the alloying is done in the strongly reducing environment of thegraphite mold instead of the more desirable neutral crucible. This maybe partly overcome by lining the mold. Except that a slightly longerheating may be found preferable before the application of the increasingpressures accompanied by vibration the process of the mold step issubstantially the sa-me. Both the one and two step methods as hereindefined are a part of the invention.

In the description of the process it was stated that the heating step inthe mold was carried out in an induction furnace. An apparatus which Ihave made up and successfully used with.

my process is illustrated in Figure 5 and comprises a pair of uprightmembers 2 and 4 suitably supported at 6 on the floor or other base andconnected near the bottom by angle irons or the like 8 to provide a firmfoundation. Spaced above the lower member may be projections I0 on whichcan be Aplaced an asbestos or other insulating It will be understoodthat varying the board l2 which'extends between the uprights to supportthe furnace I4. As such a boardwill not carry any substantial load, arefractory plug I6 is placed on the base members I or on refractorybrick I8 and of suilicient height to go through a hole in the centralportion of the asbestos board I 2 into the lower part of the furnacecoil I4. The coil 22 ofthe induction furnace rests on the asbestos boardl2. Near the top of the apparatus the uprights are connected by suitablereenforcing members 24 and 26 conveniently angle` irons. Slidable uponthe uprights. a relatively heavy steel bar 28, which may weigh about 150pounds,is mounted. Means comprising chains attached to a pawl andratchet mechanism 32, 34 are also provided to raise and lower the steelbar and between the top connecting members and the steel bar is placed ahydraulic jack 35 which, when pressure is applied, will force theconnecting member 38 and steel bar 28 downwardly. Within the coil 22 ofthe induction furnace i4, which may be helical copper tubing 40 throughwhich water may be circulated for cooling, is placed a refractory sleeve42 of quartz which may have a mica layer 44 on the outside. Therefractory sleeve is lined with a composition i6 known as Norblack, erlampblack, within which is a graphite sleeve 38, which is heated whenthe high frequency current is passed 4through the copper coil by thewires 5U. The inner diameter 4of the graphite is suiciently large toreceive either the crucible for the preailoying treatment or the moldand may have a cover 52.

The molds Figures 1 to 4 are made from a re fractory material thatretains its strength at the temperatures involved and may be made fromgraphite rods of a few inches in length and of a diameter which can bereceived within the lining. One face of the mold El) is drilled, ifcircular pieces of alloy are to be made, or milled where tool bits aredesired. The recesses formed are of the size which the nal product is tohave. Where the recesses 82 are formed by milling, su1t able stops orside pieces $4 must also be inserted to close the ends of the slots $2milled out. Each recess is then closely iitted with a plug Si of suchheight that when it is forced downwardly within the recess to the vpointwhere its upper surface coincides with that of the mold that thedimensions of the uniilled space correspond to those of the finishedarticle. It is usually preferable that the plugs 66 correspond with thelarger surface of the article formed. When the molds il have been illledwith powdered alloy il ln the manner above described, the plugs willproject substantially from the upper surface of the mold (Figure 3) andin this condition are placed witbin the induction furnace I4 preferablyresting upon a graphite plug I6 which in turn is supported by the crossmembers 8 through the refractory brick I8 below the asbestos board abovedescribed. The graphite post 54 is rested upon the plugs 66 and projectsout of the top of the coil for a short distance where it may be engagedby the steel bar 28 when it has been slightly lowered. The space betweenthe graphite postand the edge of the coil is conveniently closed by anannular refractory disc as for example 52.

When the steel bar 28 has been lowered to rest upon the graphite post54, the weight of the bar exerts pressure on the plugs Si and maintainsthis slight pressure upon the material within the mold. This pressure issuilicient to maintain the contents of the mold in contact with thewalls thereof.

brought up to the proper temperature by the.

passage of current vthrough the coils, the heat is continued to insurethorough alloying of the constituents. For relatively small pieces amatter of a few minutes as above described, is sudicient.

Pressure is then applied by operation of the hydraulic jack 35 throughthe medium of a lever attached thereto Vat 3l to force the steel bardownwardly and away from the upper cross member. The operator byreciprocating the ha-ndle of the hydraulic jack gradually increases thepressure upon the plugs and in turn upon the heated alloy i within themold. The pressure as exerted by the hydraulic jack is applied graduallyin a manner which an experienced operator learns to feel and increasedslowly but continually until as high a pressure as the mold willwithstand has been imposed.

Coincident with the application of the increasing pressures, and in someinstances during the application of the slight pressure exerted by thesteel bar, the apparatus is subjected to vibration j which istransmitted to the heated alloy. For small operations the vibration isattained by rapidly striking the steel bar with a hammer. The apparatusmay comprise mechanical or electrical means @9 for setting up thevibrations. In most instances it has been found preferable to producethe vibration by impact against the steel bar, or other equivalentmember having a large mass as compared to the striking object.

The maximum pressure will usually be coincident with the driving of theplug to the point where it is nush with the surface of the mold and asthe graphite post d and enlarged portion 55 usually covers several plugsor at any rate is larger than any single plug, any further pressure isexerted over the entire surface of the mold. Gage pressures 35 on a tenton hydraulic jack have been as high as 6000 pounds where three toolbits, 21/2 by by :A3 inches were made in a single mold before the plugswere driven to the point where they were flush with the surface of themold.

When the material is prealloyed as in the twostep process abovedescribed, the crucible may be put into the same electric furnace i0 inplace of the mold but in such cases, of course, the pressure applyingapparatus is not necessary nor used.

Alloys prepared according to the process of this invention with thecompositions set forth or with small amounts of other metals such astin, vanadium, zinc, etc., which preferably do not have a suillcientafnty for carbon to form carbides at the expense of the titanium carbideare Very useful industrially for the purposes heretofore recognized. Thetitanium alloys are particularly useful as or for cutting tools. Theirgreat strength, toughness, freedom from internal strains, and hardnesscoupled with high heat resistance and freedom from cratering providetools for fast cutting at high surface speeds. Such advantageousproperties are not `at the expense of diculty in keeping the tools inbest cutting condition because the alloy may be readily ground as abovedescribed. A particular abrasive application of the instant alloys is ingrinding wheels. For example, an alloy of about the following analysis,titanium carbide 60%, aluminum 25%, nickel and chromium may be formed asa Wheel with a diamond abrasive surface, or for mounting diamondsgenerally.

While the invention has been described in great detail as to certainpreferred embodiments these are to be considered as illustrative of theinvention and not in limitation thereof.

' What is claimed is:

fallen below the melting point of any constituent of the alloy.

2. The process for preparing a titanium carbide alloy which comprisesheating titanium car bide and an auxiliary metal to a temperature abovethe melting point of the auxiliary metal and below the melting point ofthe titanium carbide then gradually applying increasing pressures to thealloy accompanied by vibration until the temperature has fallen belowthe melting point of any constituent of the alloy.

3. 'I'he process for preparing a titanium carbide alloy which comprisesheating titanium carbide and auxiliary metals comprising chromium andnickel to a temperature above the melting point of at least one oi theauxiliary metals and below the melting pointfof the titanium carbidethen gradually applying increasing pressures to the alloy accompanied byvibratien until the temperature has fallen below the melting point ofany constituent of the alloy.

4i. The process for preparing hard metal carbide alloys which comprisespreparing a composition containing at least fifty percent of titaniumcarbide and from five to fifty percent of auxiliary metal, placing thecomposition in a mold, heating to an alioying temperature above themelting point of an auxiliary metal and below the melting point of thetitanium carbide while applying a slight pressure to maintain the heatedcomposition in contact with the mold, stopping the application of heatand gradually applying increasing pressures until the alloy has beencompressed in the ratio of 80 to 125 grams of original mixture to eachcubic inch of nnished alloy and the temperature is below the meltingpoint of any constituent of the alloy.

5. The process for preparing hard metal carbide alloys which comprisespreparing a composition containing at least fifty percent of titaniumcarbide and from five to fifty percent of auxiliary metal comprisingchromium and nickel, 'placing the composition in a mold, heating to analloying temperature above the melting point of the nickel and below themelting point of the titanium carbide while applying a slight pressureto maintain the heated composition in contact with the mold, stoppingthe application of heat and gradually applying increasing pressuresuntil the alloy has been compressed in the ratio of '80 to 125 grams oforiginal mixture to each cubic inch of nished alloy and the temperatureis below the melting point of any constituent of the alloy.

6. The process for preparing hard metal car bide alloys which comprisesprepsing a composition containing at least fifty percent of a hard metalcarbide and from ve to fty percent of auxiliary metal, placing thecomposition in a mold, heating to an alioying temperature above themelting point of an auxiliary metal and below the melting point of themetal carbide while applying a slight pressure to maintain the heatedcomposition in contact with the mold.

heating to an alloying temperature above the' melting point of anauxiliary metal and below the melting point of the titanium carbidewhile applying a slight pressure to maintain the heated composition incontact with the mold, 'stopping the application of heat and graduallyapplying increasing pressure accompanied by vibration until the alloyhas been compressed in the ratio ci @il and 125 grams oi' originalmixture to each .cubic inch of :nished alloy and the temperature isbelow the melting' point of any constituent ci the alloy.

3. The process for preparing hard metal carbide alloys which comprisespreparing a composition containing atleast fty percent of titaniumcarbide and from five to nity percent of auxiliary metal comprisingchromium and nickel, placing the composition in a mold, heating to analloying temperature above the melting point of the nickel and below themelting point of the titanium carbide while applying a slight pressureto main- 'Tcain the heated composition in contact with the mold,stopping the application of heat and gradually applying increasingpressures accompanied by vibration until the alloy has been compressedin the ratio of 80 to 12'5 grams of original mixture to each cubic inchof finished alloy and the temperature is below the melting point of anyconstituent of the alloy.

9. The process for preparing hard metal carbide alloys which comprisesheating a mixture of at least fifty percent of a hard metal carbide withauxiliary alloying metals under non-oxidizing conditions to atemperature above about 2000" centigrade and until the mixture isalloyed to iorm a slightly shrunk friable material, breaking up the saidmaterial, placing from 80 to 125 grams of the powdered material percubic inch of iinished alloy in a mold, heating the material until it isagain at the alloying temperature, stopping the application of heat andgradually applying increasing pressures accompanied by vibration untilthe alloy has been compressed to the pre determined size and thetemperature is below the melting point of any constituent of the alloy.

i0. The process for preparing hard metal carbide alloys which comprisesheating a mixture of at least nity percent of titanium carbide withauxiliary alloying metals under non-oxidizing conditions to atemperature above about 0 centigrade and until the mixture is alloyed toform a slightly shrunk friable material, breaking up the said material,placing from 80 to 125 grams of the powdered material per cubic inch offinished alloy in a mold, heating the material until it is again at thealloying temperature, stopping the application otheat and graduallyapplying increasing pressures accompanied by vibration until the alloyhas been compressed to the predetermined size and the temperature isbelow the melting point of any constituent of the alloy.

1l. The process for preparing hard metal carbide alloys which comprisesheating a mixture of at least fifty percent of titanium carbide withchromium and nickel under non-oxidizing conditions to a temperatureabove about 2000 centigrade and until the mixture is alloyed to form aslightly shrunk friable material, breaking up the said material, placingfrom 80 to 125 grams of the powdered material per cubic inch of iinishedalloy in a mold, heating the material until it is again at the alloyingtemperature, stopping the application of heat and gradually applyingincreasing pressures accompanied by vibration until the alloy has beencompressed to the predetermined size and the temperature is below themelting point of any constituent of the alloy.

i2. The process for preparing hard metal carbide alloys which comprisesheating a mixture of approximately seventy-ve percent of titaniumcarbide with approximately eight percent of chromium and seventeenpercent of nickel under nonoxidizing conditions to a temperature aboveabout 2000 centigrade and until the mixture is alloyed to form aslightly shrunk friable material, breakihg up the said material, placingfrom 80 to 125 grams of the powdered material per cubic inch of finishedalloy in a mold, heating the material until it is again at the alloyingtemperature, stopping the application of heat and gradually applyingincreasing pressures accompanied by vibration until the alloy has beencompressed to the predetermined size and the temperature is below themelting point of any constituent of the alloy.

13. The process for preparing a titanium carbide alloy which comprisesheating titanium carbide, a boride and auxiliary metals comprisingchromium and nickel to a temperature above the melting point of at leastone oi the auxiliary metals and below the melting point of the titaniumcarbide then gradually applying increasing pressures to the alloyaccompanied by vibration until the temperature has fallen below themelting point of any constituent of the alloy.

PETER WRIGHT.

